Relationship Between Strength, Power, Speed, and Change of Direction Performance of Female Softball Players.pdf

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Strength and Performance in Female Athletes
for the importance of the information and the limitations of
the results. Additionally, the findings of this research is
limited to the small population of female softball players with
similar training experience, but the unique results of this
study highlights the importance of investigating groups with
limited research in the literature.
There were very strong and significant negative correlations between BW and relative strength (r = 20.83 to 20.89)
but only nonsignificant negative correlations to VJH (r =
20.32 to 20.57) at pre, mid, and posttesting (Table 1).
Further, there were also strong to very strong positive
correlations between BW and change of direction and speed
times at pre, mid, and posttesting (r = 0.70–0.93) (Table 1).
The level of correlation varied only slightly from pre, mid to
post values. However, at the post measurement, only BWand
505 ND performances were correlated to a significance level
of p , 0.01, but all measures other than VJH were still
significant to a level of p , 0.05. The strongest relationships
seem to occur at midtesting (Table 1). Although the strength
of the relationship between BW varies during the season, it
can still be concluded that the smaller-sized athletes excel in
the variables of speed, change of direction, and relative
strength. However, this should not be interpreted as smallersized athletes will perform better in the sport of softball.
It is important to note that the nature of softball causes
many athletes to be selected for speed and change of direction
ability, whereas others rely on maximal hitting power for their
performance, which is positively correlated to lean body mass
(26). Therefore, athletes of higher body mass are often
termed ‘‘power hitters’’ and do not rely on maximal speed to
increase their on-base percentage or contribution to the
game. Therefore, even in a highly trained squad, a strong
correlation may exist between BW, speed, and change of
direction performance, but this correlation should be fully
examined with other performance characteristics, such as
throwing velocity, bat velocity, and batted ball velocity before
drawing conclusions on the importance of having lower BW
in these athletes.
Several studies have found significant relationships between VJH and a measure of sprint performance in male and
female athletes (4,8,28–30). However, similar to Maulder
et al. (14), this study did not result in significant correlations
between VJH and any measure of running speed at any point
in the season, nor did any correlation reach a level deemed
very large and could explain at least 50% of the variance in
the 2 measures (Table 2). There are 3 major justifications for
the difference in the findings of this investigation. First, VJ
performance in softball players does not comprise a significant part of their game or skill practice, especially when VJ
performance is measured without the use of an arm action.
Yet, in many sports, jumping is a more common aspect of
performance or training. For example, track and field athletes
regularly perform lower body plyometric exercises, and
soccer athletes regularly jump to head the ball. Therefore,
a strong correlation between VJ performance (even without




Journal of Strength and Conditioning Research

the use of an arm swing) and sprint speed in these athletes
may be because of a trained ability in the VJ. Further,
a transfer of learning may occur in their ballistic legperformance during running (8,28,29). However, Maulder
and colleagues did not find a significant correlation (r =
20.13) between 10-m sprint performance in male track
athletes and countermovement jump height (without the use
of an arm swing). Therefore, when considering the relationship between VJ performance and sprint performance, one
must consider the influence of the type of VJ performed (arm
swing or no arm swing) and the effect of transfer of learning
opportunities during training for the athletes. Second, level
(high school vs. collegiate) of the athletes may result in
varying degrees of correlation between VJ and sprint speed.
Previous studies involving female athletes investigated high
school and college-age female athletes (8,23,28). The
correlation between VJH and measures of sprint performance
varied (r = 20.49 to 20.64) in high-school track and soccer
female athletes and stronger correlations were found (r =
20.61 to 20.79) among mixed female collegiate athletes
(8,23,28). Vescovi and McGuigan (28) found correlations that
explained more than 50% of the variance between countermovement jump height (without the use of arm swing) and
sprint speed (18.3, 27.4, and 36.6-m times) in collegiate soccer
and lacrosse players; however, the findings of this study did
not show correlations near this strength (r = 20.21 to 20.58).
This variability may also be attributed to the sporting
background of the athletes.
Finally, justification for the difference in the findings of this
study may be the time in the training cycle at which the
testing occurred. This study is the first to our knowledge to
track the correlations in strength, power, speed, and change of
direction relationships through a competitive season. When
observing the relationship between VJ and sprint performance, it is interesting to note that the relationships in this
study are low (r = 20.21 to 20.36) at the pre and posttesting
but are higher during midtesting where improved moderate
relationships (r = 20.36 to 20.58) occurred. Therefore, the
point in a training cycle (off season, midseason, and
postseason) may be a confounding factor that can alter the
relationship of these 2 or many variables because of factors
such as accumulated fatigue or focus for improvement in the
macrocycle of training.
In conclusion, one may assume VJH capability is a function
of coordination and jump training practice rather than
a measure that explains sprint performance in these female
softball players. However, VJH measured inclusive of an arm
swing during the jump may result in different findings. Young
or untrained individuals are probably more homogenous in
their athletic abilities; where those who excel in one aspect of
athletic performance may excel at most aspects, which may
explain the strong correlations in other studies (8,28), while
those of a greater training age begin to differentiate their
athletic skills. A similar hypothesis may be made about
female athletes as well; however, more research is needed to